[Bug c++/89345] New: gcc9 <new> uses constexpr token, can you change to _GLIBCXX_CONSTEXPR ?

[mib.bugzilla at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89345

            Bug ID: 89345
           Summary: gcc9 <new> uses constexpr token, can you change to
                    _GLIBCXX_CONSTEXPR ?
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mib.bugzilla at gmail dot com
  Target Milestone: ---

In the patch to add destroying_delete, (Implement P0722R3, destroying operator
delete.) the constexpr token is used directly, can you modify this to use the
macro e.g. _GLIBCXX_CONSTEXPR. For example, recently the clang compiler
predefines __cpp_impl_destroying_delete and this causes the <new> header to
fail compilation if compiling with option -std=c++98.  

This issue is discussed here, https://reviews.llvm.org/D55741

Thanks and regards
--Melanie Blower
(I work on the Intel C++ compiler)